The present invention relates to a forced cooling rotary electric machine configured so that cooling gas is caused to flow forcedly by a self-cooling fan provided on a rotating shaft or a separate type air blower to cool internal equipment in the rotary electric machine such as a turbine generator and an electric motor. More particularly, it relates to a forced cooling rotary electric machine suitable for cooling a stator core that is subjected to a variable magnetic field and is heated.
Generally, to cool a stator core and to uniformize the temperature distribution in the axial direction of the stator core (stacking direction of silicon steel plates), a forced cooling rotary electric machine in which a plurality of air ducts are provided in the axial direction of a stator core has already been proposed as shown, for example, in JP-A-2006-109616 (FIGS. 6 and 7).
In such a forced cooling rotary electric machine, depending on the type and construction of machine, the temperature distribution in the axial direction of the stator core is uniformized by changing the ventilation cross-sectional areas of the air ducts while the core stacking pressure between the adjacent air ducts is made equal, or the temperature distribution in the axial direction of the stator core is uniformized by changing the core stacking pressure between the adjacent air ducts each having the same ventilation cross-sectional area.